Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
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Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#2This approach has been tried before. Bill Softky describes a startup he'd worked for using a similar sound-transduction continuous non-invasive blood-pressure monitoring technique. It ... had problems:
Our non-invasive device was supposed to measure blood pressure just as accurately [as an arterial line], but without the cutting, using specially-sculpted sonic vibrations and fancy algorithmic analysis, which was my job. The overall challenge was like measuring the pressure inside a bottle without opening it. Our device worked fine, in that our algorithmically-estimated blood pressure moved up and down, beat to beat, in lockstep with the actual blood pressure. The problem was that our estimate also moved up and down at other times as well, say when the patient moved her fingers, rotated her arm, or took vaso-constricting drugs like nicotine. I spent most of a year understanding these problems, and understanding they couldn’t be solved before our funding ran out. That was when an old-timer taught me an important lesson of measurement: it’s fairly easy to calculate a signal which correlates with what you want to measure, the way our vibration-estimate correlated with actual blood pressure. It’s much harder, though, to calculate a signal which does NOT correlate with what you DON’T want to measure, like arm motion.
https://www.linkedin.com/pulse/monster-monetization-bill-sof...>
I'd be exceedingly curious as to how the CalTech team have solved that non-correlation problem.
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#3This approach has been tried before. Bill Softky describes a startup he'd worked for using a similar sound-transduction continuous non-invasive blood-pressure monitoring technique. It ... had problems: Our non-invasive device was supposed to measure blood pressure just as accurately [as an arterial line], but without the cutting, using specially-sculpted sonic vibrations and fancy algorithmic analysis, which was my j…
Looking at the diagram I’d suspect they use accelerometer information from both the wrist watch and the upper arm mounted sensor to remove the effects of arm motion. At simplest it could only check when the arm is in a neutral position. But I’d expect they did something more complex/better than that.
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#4As a person who had a hypertensive crisis late last year, nothing boils my blood (yes, a pun, I am fine now) more than how people measure blood pressure incorrectly in doctors offices and even hospitals. There are many different things than can increase a BP measurement above the "baseline" including talking, moving around, not having rested but also just waking up, not being in a supported position, only a single value, etc. Most of the major health agencies (AMA,AHA,CDC, etc in the US) have recommendations on how to do it properly, but in medical situations like doctors offices and hospitals, these are rarely done as they take too much time. A single measurement is not sufficient and can result in misdiagnosis.
A more reliable way to measure a continuum would make a difference, but I imagine it would still require time to collect as BP is a dynamic value that changes with behavior, posture and activity.
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#5As a person who had a hypertensive crisis late last year, nothing boils my blood (yes, a pun, I am fine now) more than how people measure blood pressure incorrectly in doctors offices and even hospitals. There are many different things than can increase a BP measurement above the "baseline" including talking, moving around, not having rested but also just waking up, not being in a supported position, only a single va…
As an adult with a congenital heart defect and white coat hypertension, I can relate. Once, a nurse took my blood pressure and immediately freaked out as I was sitting calmly on the exam table. She took it again in the same arm, then hurriedly took it in each of my other limbs before throwing her hands up.
Often, I would arrive at the cardiology office having made my way through downtown traffic to find a parking space and walk across the pedway. Then I'd find a seat as far away as possible from all the noisy children there to remind me that I should be dead. No wonder my BP is higher than usual. And you're the one freaking out?
I got so used to nurses tossing out every recommendation for measuring BP that I started taking it myself at home before visits just to prove the point. Eventually, as I grew older, my BP rose to a point where it actually needed to be addressed. I am now on medication. But I have yet to find a nurse anywhere that has taken time to follow even one recommendation for properly taking BP.
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#6This approach has been tried before. Bill Softky describes a startup he'd worked for using a similar sound-transduction continuous non-invasive blood-pressure monitoring technique. It ... had problems: Our non-invasive device was supposed to measure blood pressure just as accurately [as an arterial line], but without the cutting, using specially-sculpted sonic vibrations and fancy algorithmic analysis, which was my j…
Paper: https://academic.oup.com/pnasnexus/article/3/7/pgae252/77177...
They tested on the carotid artery. I don't know whether they're concerned with addressing issues of wearing this while active. It seems more likely that it will be used in a clinical setting.
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#7[dead]
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#8This approach has been tried before. Bill Softky describes a startup he'd worked for using a similar sound-transduction continuous non-invasive blood-pressure monitoring technique. It ... had problems: Our non-invasive device was supposed to measure blood pressure just as accurately [as an arterial line], but without the cutting, using specially-sculpted sonic vibrations and fancy algorithmic analysis, which was my j…
It’s just a blurb from a college PR team. As someone that came from academia, they don’t have to have solved any of that because these are generally pretty worthless. It can be as small as someone in a lab discovered how to do the smallest thing and the college wants to run with it to look good.
Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#9As a person who had a hypertensive crisis late last year, nothing boils my blood (yes, a pun, I am fine now) more than how people measure blood pressure incorrectly in doctors offices and even hospitals. There are many different things than can increase a BP measurement above the "baseline" including talking, moving around, not having rested but also just waking up, not being in a supported position, only a single va…
As an adult with a congenital heart defect and white coat hypertension, I can relate. Once, a nurse took my blood pressure and immediately freaked out as I was sitting calmly on the exam table. She took it again in the same arm, then hurriedly took it in each of my other limbs before throwing her hands up. Often, I would arrive at the cardiology office having made my way through downtown traffic to find a parking spa…
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Re: Caltech Develops First Noninvasive Method to Continually Measure Blood Pressure
#10[dead]
This isn't measuring blood pressure, isn't it?